Localized and systemic infections represent one of the most serious post surgical complications. Over the past fifty years tremendous advances in materials, training and antimicrobial therapies have significantly reduced the number of life-threatening post operative infections. The development of pre-sterilized disposable surgical dressings, medical instruments, gowns, drapes and other materials have helped reduce infection frequency. However, the development of improved antimicrobials represents the single most significant advance in infection control.
Deep tissue infections can result when medical implants become contaminated prior to or during surgical placement. When oral or parenterally administered antimicrobials fail to effectively control and eliminate the infection, the medical implant may have to be removed. Removal requires additional surgical procedures to treat the infection as well as to re-implant the device after the infection completely resolves. Moreover, once deep tissue infections are established, long term antimicrobial therapy and hospitalization may be required. These additional procedures increase the costs associated with device implantation, subject the patient to discomfort and in rare circumstances can result in severe long term health issues such as, increasing the threat of permanent disfigurement.
Coating implantable medical devices with antimicrobial compounds allows for deep tissue drug delivery that can significantly reduce the risk of post implantation infections. Coating procedures should employ broad spectrum antimicrobials that are effective against most post surgical infections, especially MRSA (multiple-resistant Staphylococcus aureus) infections. The antimicrobials must be soluble in physiological fluids and stable enough to survive processing steps required to successfully coat the medical device. Ideally, a synergistic antimicrobial combination should be used. In addition, the size, shape and composition of the medical devices can significantly impact the success of the coating procedure.
One representative example of an implantable medical device coated with antimicrobial compounds include INHIBIZONE treatment products developed and sold by American Medical Systems of Minnetonka, Minn. These products generally include an implantable medical device such as, for example, components comprising a penile implant such as the AMS 700™ Series that have been coated with a combination of rifampin and minocycline using the processes and systems as disclosed in U.S. Pat. Nos. 6,534,112 and 6,916,377, which are herein incorporated by reference. The INHIBIZONE coating is readily dissolved when exposed to the warm, moist conditions found within the body such that the instances of infection are significantly reduced.
While, the INHIBIZONE treatment products are successful in reducing the occurrence of infection with implantable medical devices, it would be advantageous to further improve upon the coating process so as to more precisely control loading of the implantable medical device with the antimicrobial agent.